WO2023156168A1

WO2023156168A1 - Extrusion die and extrusion system

Info

Publication number: WO2023156168A1
Application number: PCT/EP2023/052010
Authority: WO
Inventors: Mathias Geyer; Walter Breuning; Lasse LIMBACH
Original assignee: KraussMaffei Extrusion GmbH
Priority date: 2022-02-21
Filing date: 2023-01-27
Publication date: 2023-08-24
Also published as: TW202344369A; DE102022104009A1

Abstract

The invention relates to an extrusion die (100), in particular pipe extrusion die, for producing a hollow plastic profile, in particular a plastic pipe, comprising: at least two melt inlets (102a, 102b, 102c); at least two melt channels (104a, 104b, 104c); and a melt outlet (106), wherein a first melt channel (104a) extends between a first melt inlet (102a) and the melt outlet (106) and a second melt channel (104b) extends between a second melt inlet (102b) and the melt outlet (106), the first melt channel (104a) and the second melt channel (104b) being thermally separated from each other at least in sections. The invention also relates to an extrusion system comprising at least one extruder and an extrusion die (100).

Description

Extrusion tool and extrusion line

The invention relates to an extrusion tool, in particular a pipe extrusion tool, for example a pipe head. In addition, the invention relates to an extrusion system with such an extrusion die.

Extrusion tools are usually connected downstream of an extruder arrangement, for example directly, so that the melt provided by the extruder arrangement, in particular plastic melt, can be brought into a desired shape by the downstream extrusion tool. Flat nozzles, tubular tools, profiles etc. are known as extrusion tools.

In the case of pipe extrusion tools, also known as pipe heads for short, it is also known to heat them radially inside and/or outside inside the housing, ie far in front of the nozzle, for example with the aid of ceramic heating strips. Particularly in the case of large pipe heads, the interior of the pipe head is heated with the aid of a tempering system that works with a tempering medium. Such temperature control has the advantage that heat can not only be supplied to the melt, but can also be removed.

For example, a device for producing a hollow plastic profile is known from document DE 10 2010 025 524 A1, which has an extrusion die with a melt channel, an extruder feeding the melt channel with plastic melt, and a suction device for sucking air through the inside of the profile counter to the extrusion direction. Internal pipe cooling can be provided by the air duct system.

Furthermore, DE 197 44 515 A1 discloses a method and a device for producing an endless extruded profile strand by coextrusion of different materials, the extrusion temperatures of the different materials differing from one another and the different materials have separate, each separately temperature-controlled and thermally channels that are insulated from one another are fed to an extrusion tool, where they are brought together and extruded, preferably under pressure.

Further technological background can be found in US Pat. Nos. 5,641,445 A, US 5,516,474 A, WO 2008/004 329 A1, DE 35 32 996 A1 and DE 30 44 535 A1.

In the production of multi-layer plastic products, which have to be extruded from plastics with significantly different processing temperatures, however, the design of the known extrusion tools for pipe extrusion has a number of disadvantages. Above all, there is the risk of degradation of the plastics and limited formability of the plastic melt. With the known design, various multi-layer plastic products, such as multi-layer pipes, cannot be produced or can only be produced in a multi-stage process. Plastics that have to be processed at different temperatures for technical reasons cannot be processed within the known pipe extrusion tool. Uncontrolled heating of individual plastic layers would also lead to defects in the pipe. With regard to the extrusion of multi-layer pipes, the usual design also significantly limits the throughput of the tools and limits the diameter of pipes that can be produced.

The object of the invention is to structurally and/or functionally improve an extrusion tool as mentioned at the outset. In addition, the invention is based on the object of improving the structure and/or functionality of an extrusion system as mentioned at the outset. It is therefore an object of the present invention to provide an extrusion tool or an extrusion system which reduces or eliminates the disadvantages identified in connection with the prior art. In particular, it is the object of the present invention to provide a pipe extrusion tool with which plastic melts can be processed at different temperatures in order to be able to produce multilayer pipes of higher quality in a single-stage process. Furthermore, the throughput should be improved and the coverage of a wide pipe dimension window per tool should be made possible. The object is achieved with an extrusion tool having the features of claim 1. The object is also achieved with an extrusion system having the features of claim 20. Advantageous designs and/or developments are the subject matter of the dependent claims.

One aspect relates to an extrusion tool, in particular for producing a hollow plastic profile. The plastic profile can be a plastic tube, for example a multi-layer tube. The extrusion tool can be used and/or designed for use in an extrusion system. The extrusion tool may be a pipe extrusion tool, such as a pipe head.

The extrusion die has at least two melt inlets. The at least two melt inlets can each be designed for connection to an extruder, in particular an extruder outlet. For example, the extrusion tool can have exactly two melt inlets or exactly three melt inlets. The number of melt inlets can correspond to the number of layers of the multi-layer profile or multi-layer pipe to be produced.

The extrusion tool has at least two melt channels. The at least two melt channels can each be designed to guide and/or conduct and/or receive a plastic melt. For example, the extrusion die can have exactly two melt channels or exactly three melt channels. The number of melt channels can correspond to the number of layers of the multi-layer profile or multi-layer pipe to be produced.

The extrusion tool has at least one melt outlet. The extrusion die can have one, for example exactly one, melt outlet. The melt outlet can be designed in such a way that the plastic melt and/or the plastic hollow profile produced can be output and/or transferred to a nozzle and/or a set of nozzles. The extrusion tool can have the nozzle and/or the nozzle set. The nozzle and/or the nozzle set can be arranged and/or fastened at the melt outlet. The nozzle and/or nozzle set can be replaceable. the nozzle and/or the nozzle set may have a dome. The nozzle and/or the nozzle set can be designed to form and/or shape specific or different profile or tube dimensions, such as tube diameters. The nozzle set may include the nozzle and the mandrel.

In the present aspect, the extrusion die has a first melt channel and a second melt channel. Furthermore, the extrusion die has a first melt inlet and a second melt inlet. The first melt channel runs between the first melt inlet and the melt outlet. The second melt channel runs between the second melt inlet and the melt outlet. The first melt channel and the second melt channel are thermally separated from one another at least in sections. This can be done by thermal separation. This makes it possible to bring about different temperature control of the plastic melt moving through the melt channels and thereby to optimally influence the different plastic materials to be processed. It is thus possible to feed plastic materials with very different temperatures into the extrusion tool after plastification and to keep them at this temperature during the material distribution, so that temperature equalization takes place in particular only in the extrudate that has been stacked on top of one another.

Furthermore, the extrusion die has a third melt inlet and a third melt channel. The third melt channel runs between the third melt inlet and the melt outlet. The first melt channel and the third melt channel are thermally separated from one another at least in sections. Additionally or alternatively, the second melt channel and the third melt channel can be thermally separated from one another at least in sections. Several melt channels can be provided. The plurality of melt channels can be thermally separated from one another at least in sections.

The extrusion tool can have at least two distribution elements. For example, the extrusion tool can have exactly two or exactly three distribution elements. The number of distribution elements can the number of Correspond layers of the multi-layer profile or multi-layer tube to be produced.

The extrusion tool can have a first distribution element and a second distribution element. The first melt channel can be formed and/or delimited at least in sections by the first distribution element and the second distribution element. The extrusion tool can have a connecting piece. The connection piece can be pot-shaped and/or cylindrical, for example hollow-cylindrical. The connecting piece can have a base section extending in the radial direction and a wall section extending in the axial direction, such as the direction of extrusion. The connecting piece can be arranged essentially between the first distribution element and the second distribution element in the axial direction, such as the extrusion direction. The connection piece can be attached to the second distribution element, for example screwed to it. The first melt channel can be formed and/or delimited at least in sections by the first distribution element and the connection piece.

The extrusion tool can have a housing. The housing can be made in several parts. The housing can have several housing sections or housing parts. The distribution elements can be arranged inside the housing. The second melt channel can be formed and/or delimited at least in sections by the second distribution element and a housing section of the extrusion die.

The extrusion tool can have a third distribution element. The third melt channel can be formed and/or delimited at least in sections by the third distribution element and a housing section of the extrusion die. The second melt channel can be formed and/or delimited at least in sections by the third distribution element and the second distribution element.

The first distribution element and the second distribution element can be thermally separated from one another at least in sections. The first distribution element and the third distribution element can be separated thermally at least in sections be separated. Additionally or alternatively, the second distribution element and the third distribution element can be thermally separated from one another at least in sections. Several distribution elements can be provided. The multiple distribution elements can be thermally separated from one another at least in sections.

The distribution elements or the first distribution element and/or the second distribution element and/or the third distribution element can be designed in one piece or in multiple pieces, for example in two pieces. For example, a distribution element can include a pre-distribution element and a helical distribution element. The pre-distribution element can have a main channel and/or at least one pre-distribution channel. The spiral distribution element can comprise at least one secondary channel. The at least one secondary channel can end helically in the peripheral surface of the spiral distribution element. The main channel can merge into the at least one pre-distribution channel and/or the at least one secondary channel. The at least one pre-distribution channel can merge into the at least one secondary channel. The distribution elements or the first distribution element and/or the second distribution element and/or the third distribution element can be designed as spiral distributors. The spiral distributor can be an axial spiral distributor. The spiral distributor can be essentially cylindrical, for example hollow-cylindrical. The spiral distributor can be designed in one piece or in multiple pieces. The spiral distributor can have a main channel. The main channel can be an entry channel, such as a melt entry channel. The spiral distributor can have at least one secondary channel which is in particular fluidic and/or fluidic connection, such as a fluid connection, with the main channel. The at least one secondary channel can end helically in the peripheral surface of the spiral distributor. The main channel can merge into the at least one secondary channel. The at least one secondary channel can be an outlet channel, such as a melt outlet channel. The at least one secondary duct can be a spiral manifold duct. The spiral distributor can have several side channels. The several secondary channels can be fluidically connected to the main channel on the inlet side or open into it. The multiple sub-channels can form a helical arrangement. The plastic melt can be fed into the spiral distributor via the main channel. The plastic melt can be conducted from the main channel further into the at least one secondary channel or into the plurality of secondary channels. In that at least The plastic melt can be brought to a homogeneous and/or hollow shape in a side channel or in the plurality of side channels. The main channel and/or the at least one secondary channel or secondary channels can be part of a melt channel and/or form and/or define this at least in sections. The main duct and/or the at least one secondary duct or the secondary ducts and/or the at least one pre-distribution duct or pre-distribution ducts can/can be designed at least in sections as a bore or groove.

The distribution elements or helical distributors can be spaced apart from one another and/or arranged one behind the other essentially in the axial direction, in particular the direction of extrusion. The distribution elements or spiral distributors can be arranged essentially concentrically or eccentrically, in particular in relation to the extrusion axis, in particular in the axial direction, such as the extrusion direction. The distribution elements or helical distributors can essentially be arranged overlapping and/or pushed into one another in the axial direction, in particular the extrusion direction, and/or the radial direction, in particular in sections. It is also possible within an extrusion tool to provide spiral distributors that are spaced apart from one another and/or arranged one behind the other in the axial direction, in particular the extrusion direction, and spiral distributors that are arranged in an overlapping manner and/or are pushed into one another. The at least one secondary channel or secondary channels, for example its outlet(s), of the first spiral distributor and the at least one secondary channel or secondary channels, for example its outlet / outlets, of the second spiral distributor can essentially be spaced apart from one another in the axial direction, in particular the extrusion direction /or be arranged one behind the other. The at least one secondary channel or secondary channels, for example its outlet(s), of the first spiral distributor and the at least one secondary channel or secondary channels, for example its outlet / outlets, of the second spiral distributor can essentially run in the axial direction, in particular the extrusion direction, and/or be arranged overlapping in sections in the radial direction. The at least one secondary channel or secondary channels, for example its outlet / outlets, of the second spiral distributor and the at least one secondary channel or secondary channels, for example its outlet / outlets, of the third spiral distributor can be separated essentially in the axial direction, in particular the extrusion direction be spaced and / or arranged one behind the other. The at least one secondary channel or secondary channels, for example its outlet(s), of the second spiral distributor and the at least one secondary channel or secondary channels, for example its outlet / outlets, of the third spiral distributor can essentially run in the axial direction, in particular the extrusion direction, and/or be arranged overlapping in sections in the radial direction.

The melt channels and/or melt streams can be brought together one behind the other essentially in the axial direction, in particular the direction of extrusion. The joining together of individual melt channels and/or melt streams can be realized essentially one behind the other in the axial direction, in particular the extrusion direction, and/or the radial direction, for example by means of an L-shaped or T-shaped connecting arrangement or connecting piece.

The first melt channel and the second melt channel can merge into a common annular melt channel in the direction of the melt outlet. This annular melt channel and the first and/or second melt channel can be thermally separated from one another at least in sections. The annular melt channel can be essentially concentric to the extrusion direction or extrusion axis. The annular melt channel can be an annular gap melt channel. The annular melt channel can be designed in such a way that an annular gap flow of the plastic melt can be generated. At least two melt streams can be brought together in the annular melt channel.

In the present aspect, the second melt channel and the third melt channel merge into a common annular melt channel in the direction of the melt outlet. This annular melt channel and the first and/or second and/or third melt channel can be thermally separated from one another at least in sections. In the present aspect, the first melt channel and the annular melt channel are thermally separated from one another at least in sections. The annular melt channel can be essentially concentric to the extrusion direction or extrusion axis. The annular melt channel can be an annular gap melt channel. The annular melt channel can be designed in such a way that an annular gap flow of the plastic melt can be generated. The ring melt channel can be formed and/or delimited at least in sections by the connection piece and a housing section of the extrusion die. At least two or three melt streams can be brought together in the annular melt channel. The first melt channel can open further downstream into the annular melt channel, in particular than the second and/or third melt channel.

The respective thermal separation can be formed by a gap and/or cavity. The gap and/or cavity can be ring-shaped and/or spiral-shaped. The gap can be an annular gap, air gap or vacuum gap. The cavity can be a chamber, such as a hollow chamber and/or a vacuum chamber. The gap and/or cavity can have an inlet or inlet and/or outlet or outlet for a temperature control medium. The respective thermal separation can additionally or alternatively be formed by an insulation element. The insulation element can be arranged completely or at least in sections within the gap or cavity. The insulation element can be arranged completely or at least in sections within a melt channel. The insulation element can form and/or delimit a melt channel at least in sections. The insulation element can be cylindrical and/or cup-shaped. The insulating element can be made from steel, in particular from a steel with a low coefficient of thermal conductivity, such as high-grade steel. The steel can have a lower coefficient of thermal conductivity than the material, such as steel, of the distribution elements and/or the housing. Materials such as steels can be provided which have different coefficients of thermal conductivity. The insulating element can be made of a metal, such as steel or alloys, plastic and/or insulating material, for example wool, such as mineral wool or glass wool, or can have at least one of them. The insulating material can be an artificial and/or natural fiber insulating material. The insulation element can also have a natural material. In particular, the material of the insulation element can be designed as a poor heat conductor. The insulation element can be designed as an intermediate piece and/or connection piece for at least one distribution element, for example for the first distribution element. The insulating element can be designed as an insulating collar or insulating bush. The thermal separation and/or the insulating element can be designed as a coating, in particular an insulating coating. The coating can be provided at least in sections within the melt channels. For example, the coating can be an inner coating of the melt channel. One or the melt channels can thus be coated with an insulating coating at least in sections. The coating may be metal, such as steel or an alloy, and/or plastic. In particular, the material of the coating can be designed as a poor heat conductor.

The insulating element or the insulating collar or insulating bush can be arranged around at least one section of a melt channel, for example around at least one section of the first melt channel. The insulating element or the insulating collar or insulating bush can have at least one heating and/or cooling element. The heating and/or cooling elements can be controlled via temperature control devices. The heating and/or cooling elements can be designed as electrical and/or hydraulic heating and/or cooling elements. The heating element can be a heating tape. The heating tape can be a ceramic heating tape or a mica heating tape.

The gap or cavity can be and/or can be filled with a temperature control medium, such as heating means or coolant, for example with a gas such as air and/or with a fluid such as water and/or oil. A vacuum can essentially be provided and/or generated in the gap and/or cavity. The thermal separations, in particular the respective gaps, cavities, insulating elements, insulating sleeves or insulating bushings, can be provided or connected to temperature control devices that are independent of one another. For example, a tempering medium at a predetermined temperature can flow and/or be fed through each gap or cavity or through selected gaps or cavities in order to correspondingly temper the plastic melt in the associated melt channel, such as heating or cooling or to a predetermined temperature to maintain temperature.

At least one section of a melt channel, for example at least one section of the first melt channel, can essentially be mounted in a floating manner be. The at least one section of the melt channel can be designed and/or mounted in such a way that it can expand and/or shift at least in one direction, for example in and/or opposite to the direction of flow and/or direction of extrusion. The bearing can be provided on a distribution element, for example on the third distribution element, and/or on a housing section.

Another aspect relates to an extrusion line. The extrusion system can be set up and/or designed to produce a hollow plastic profile, such as a plastic tube, for example a multi-layer tube. The extrusion system can include an extrusion tool. The extrusion tool can be configured as described above and/or below. The extrusion plant can also include at least one extruder. The at least one extruder can be a single-screw extruder or a twin-screw extruder. The extrusion system can provide an extruder for each melt inlet of the extrusion tool.

In summary and in other words, the invention results in, among other things, an extrusion tool, such as a pipe tool/pipe head, in which a different structure is provided, so that different plastics with their different temperatures remain separate from one another for as long as possible. This can be done by thermally separating the layers or plastic melts, by tempering the layers or plastic melts and/or by bringing the layers or plastic melts together in the tool as late as possible. A thermal separation can be provided between a central and/or internal melt line (melt channel) and a distribution element, such as a spiral distributor. In addition or as an alternative, a thermal separation can be provided between the distribution element, such as a spiral distributor, and an annular gap flow. A thermal separation of the interior from the middle layer can be provided. At least one melt line (melt channel) can be mounted in a floating manner, at least in sections, for example as a floating melt feed or by floating mounting. The melt-carrying components can be pressure-resistant. For example, in particular axial, helical distributors can be provided. If the layers of melt are brought together late, for example by placing the layer close to the outlet of the tool, an influence, such as degradation of Plastics, the different layers are reduced. In this way, a separation of the temperatures can be provided by bringing the layers or plastic melt together at a later stage. The spirals of the inner layer can be shifted far forward to the nozzle set. The melt can be conducted through melt lines (melt channels) into and through the tube head. The melt line(s) can run thermally separated through the tool. The melt line(s) (melt channel) can be overhung. There is little or no contact between components of different temperatures. Furthermore, the melt line(s) (melt channel) can be heated and/or insulated. Active temperature control, such as cooling or heating, can also be provided. For example, a floating and/or thermally separated melt guide can be provided for the inner layer. Previously one-piece components can now be divided into at least two components. By using steels with different thermal conductivity coefficients, it may be possible to reduce unwanted heat conduction in the tool. As steel, stainless steel can be used as a poor conductor of heat. Components can be designed in such a way that it is possible to compensate for the different thermal expansions of the components due to different temperatures. In addition, an air layer or gap, such as an air gap, can be provided and/or incorporated between the components. Poorer heat conduction can be achieved by air gaps, especially with many boundary layers with poor heat transfer. This can drastically reduce heat conduction. The gap can also be actively tempered with a medium, such as heated or cooled. Become. The medium can be oil, water, air, etc., for example. Alternatively, a vacuum can be provided and/or generated in the gap. In this way, active cooling and/or heating with a medium can be provided.

With the invention, materials or plastic melts that have to be processed at different temperatures for procedural reasons can be processed within a tool. An optimal wall thickness distribution in the finished tube can be achieved by thermal separation and/or temperature control of the different hot materials or plastic melts. Uncontrolled heating of individual layers or plastic melts is avoided. This avoids defects in the pipe or at least greatly reduced. Buildup due to excessively high temperatures, which adversely affect production, can be prevented. Cleaning intervals can be extended due to the thermal separation. A multi-stage extrusion process can be omitted since only one tool is required. Economic throughput can be improved. Covering a wide tube dimension window per tool can be enabled.

Exemplary embodiments of the invention are described in more detail below with reference to a figure, which shows schematically and by way of example:

1 shows a sectional view of an extrusion tool.

1 shows a sectional view of an extrusion tool 100. The extrusion tool 100 is designed as a pipe extrusion tool, for example as a pipe head, for producing a hollow plastic multi-layer pipe. In the present exemplary embodiment, the extrusion tool 100 can be fed with three plastic melts in order to produce a three-layer plastic pipe.

The extrusion tool 100 comprises three melt inlets 102a, 102b, 102c, which can be fed with different plastic melts, in particular with different temperatures, via associated or connected extruders (not shown in FIG. 1). The extrusion tool 100 thus has a first melt inlet 102a, a second melt inlet 102b and a third melt inlet 102c.

Furthermore, the extrusion tool 100 comprises three melt channels 104a, 104b, 104c, namely a first melt channel 104a, a second melt channel 104b and a third melt channel 104c and a melt outlet 106. The first melt channel 104a runs between the first melt inlet 102a and the melt outlet 106. The second Melt channel 104b runs between the second melt inlet 102b and the melt outlet 106. The third melt channel 104c runs between the third melt inlet 102c and the Melt outlet 106. The individual melt channels 104a, 104b, 104c are brought together in the extrusion direction (in Fig. 1 from right to left) and end together in the melt outlet 106. The extrusion tool 100 is designed such that the two second and third melt channels 104b, 104c or whose plastic melt streams are brought together first. The first melt channel 104a or its plastic melt stream is fed further downstream in the extrusion direction at an axial distance to the two merged melt channels 104b, 104c or plastic melt streams.

The extrusion tool 100 has a first distribution element 108a, a second distribution element 108b and a third distribution element 108c. The first melt channel 104a is formed and delimited in sections by the first distribution element 108a and a connecting piece 110 . The second melt channel 104b is formed and delimited in sections by the second distribution element 108b and the third distribution element 108c. The third melt channel 104c is formed and delimited in sections by the third distribution element 108c and a housing section 112 of the extrusion die 100 .

The distribution elements 108a, 108b, 108c are each designed as axial spiral distributors, each of which has a main channel 114a, 114b, 114c and a plurality of secondary channels 116a, 116b, 116c which are in fluid communication with the respective main channel 114a, 114b, 114c include, which expire helically in the peripheral surface of the respective spiral distributor 108a, 108b, 108c. The distribution elements 108a, 108b, 108c or spiral distributors 108a, 108b, 108c are arranged one behind the other and spaced apart essentially in the extrusion direction. As can be seen in FIG. 1, the secondary channels 116b or their outlets of the second distribution element 108b are arranged downstream of the secondary channels 116c or their outlets of the third distribution element 108c in the extrusion direction and are spaced apart from them. Furthermore, the secondary channels 116a or their outlets of the first distribution element 108a are arranged downstream of the secondary channels 116b or their outlets of the second distribution element 108b in the extrusion direction and are spaced apart from them. The second melt channel 104b and the third melt channel 104c merge in the direction of the melt outlet 106 into a common annular melt channel 118 or annular gap melt channel 118, in which the two melt flows are brought together. The annular melt channel 118 is formed and delimited in sections by the connecting piece 110 and a housing section 120 of the extrusion die 100 . The first melt channel 104a opens further downstream into the ring melt channel 118, so that the melt flow of the first melt channel 104a is merged with the already merged melt flows of the second and third melt channel 104b, 104c. Immediately following this, the melt outlet 106 is provided. A nozzle set 122 is arranged at the melt outlet 106, which forms a specific pipe dimension, such as pipe diameter, and forms the plastic pipe. The nozzle set includes a nozzle 122a and a dome 122b.

The extrusion tool 100 has a plurality of thermal separations in order to process plastic melts at different temperatures within the extrusion tool 100 . In particular, the first melt channel 104a and the second melt channel 104b are thermally separated from one another at least in sections. Likewise, the first melt channel 104a and the third melt channel 104c are thermally separated from one another at least in sections. The first melt channel 104a and the annular melt channel 118 or the connection piece 110 are also thermally separated from one another at least in sections. As shown in FIG. 1, the first distribution element 108a and the second distribution element 108b as well as the first distribution element 108a and the third distribution element 108c are thermally separated from one another at least in sections.

In the present exemplary embodiment, the first melt channel 104a or the first distribution element 108a is thermally separated from the ring melt channel 118 or connection piece 110, and thus from the second and third melt channel 104b, 104c, by a gap 124. The gap 124 is designed as an annular gap. The connection piece 110 is arranged downstream of the second distribution element 108b in the extrusion direction and is screwed to it. In the gap 124 and in the extrusion direction axially between the connection piece 110 and the first distribution element 108a, an insulation element 126 is additionally arranged in an effective manner. The The first melt channel 104a is thus formed and delimited in sections by the first distribution element 108a and the insulation element 126 . The insulation element 126 is screwed to the connection piece 110 and is also used to fasten the first distribution element 108a. Furthermore, the insulating member 126 is made of a steel with a low coefficient of thermal conductivity, such as stainless steel.

Further upstream, in particular against the extrusion direction, the first melt channel 104a is thermally separated from the second and third melt channel 104b, 104c or from the second and third distribution element 108b, 108c by a gap or cavity 128. In the present exemplary embodiment, the gap or cavity 128 is wider in the radial direction than the annular gap 124 . The first melt channel 104a is additionally surrounded here in sections by at least one insulation element 130 embodied as an insulating sleeve. The insulating sleeve can have one or more cooling and/or heating elements. The heating element can be a heating tape. The heating tape can be a ceramic heating tape or a mica heating tape. Even further upstream, in particular in the area of the first melt inlet 102a, an insulating element 132 designed as an insulating bushing is arranged around a section of the first melt channel 104a. As a result, a further thermal separation of the first melt channel 104a from the two other melt channels 104b, 104c is formed.

For temperature control, a temperature control medium such as a heating medium or coolant, for example a gas such as air and/or a fluid such as water and/or oil, can also be fed into the annular gap 124 and/or the cavity 128 by means of a temperature control device. Alternatively, essentially a vacuum can be provided and/or generated in the annular gap 124 and/or the cavity 128 .

In particular, “may” denotes optional features of the invention. Accordingly, there are also developments and/or exemplary embodiments of the invention which additionally or alternatively have the respective feature or features. If necessary, isolated features can also be selected from the combinations of features disclosed here and used in combination with other features to delimit the subject matter of the claim, eliminating any structural and/or functional relationship that may exist between the features.

Reference List

Extrusion tool a-c melt inlets a-c melt channels

Melt outlet a-c distribution elements

fitting

Housing section a-c main ducts a-c subsidiary ducts

ring melt channel

housing section

Nozzle set a Nozzle b dome

gap / annular gap

isolation element

gap / cavity

Insulation element / insulating sleeve

Insulating element / insulating bush

Claims

Claims Extrusion tool (100), in particular pipe extrusion tool, for producing a hollow plastic profile, in particular a plastic pipe, comprising at least two melt inlets (102a, 102b, 102c); at least two melt channels (104a, 104b, 104c); and a melt outlet (106), wherein a first melt channel (104a) runs between a first melt inlet (102a) and the melt outlet (106) and a second melt channel (104b) runs between a second melt inlet (102b) and the melt outlet (106), characterized in that the first melt channel (104a) and the second melt channel (104b) are thermally separated from one another at least in sections. Extrusion tool (100) according to Claim 1, characterized in that the extrusion tool (100) has a third melt inlet (102c) and a third melt channel (104c) which runs between the third melt inlet (102c) and the melt outlet (106), the first melt channel (104a) and the third melt channel (104c) are thermally separated from one another at least in sections. Extrusion tool (100) according to at least one of the preceding claims, characterized in that the extrusion tool (100) has a first distribution element (108a) and a second distribution element (108b), the first melt channel (104a) being at least partially separated from the first distribution element (108a ) and the second distribution element (108b) or by the first distribution element (108a) and a connecting piece (110, 126) and/or is delimited. Extrusion tool (100) according to claim 3, characterized in that the second melt channel (104b) at least partially from the second Distribution element (108b) and a housing section of the extrusion tool (100) is formed and / or limited. Extrusion tool (100) according to at least one of the preceding claims, characterized in that the extrusion tool (100) has a third distribution element (108c), the third melt channel (104c) being separated at least in sections from the third distribution element (108c) and a housing section (112) of the extrusion tool (100) is formed and / or limited. Extrusion tool (100) according to at least one of the preceding claims 3 to 5, characterized in that the first distribution element (108a) and the second distribution element (108b) and/or the first distribution element (108a) and the third distribution element (108b) are separated from one another at least in sections are thermally separated. Extrusion tool (100) according to at least one of the preceding claims 3 to 6, characterized in that the first distribution element (108a) and/or the second distribution element (108b) and/or the third distribution element (108c) as a spiral distributor (108a, 108b, 108c ) is or are formed, wherein the spiral distributor (108a, 108b, 108c) has a main channel (114a, 114b, 114c) and at least one secondary channel (116a, 116b, 116c), the at least one secondary channel (116a, 116b, 116c) terminating helically in the peripheral surface of the spiral distributor (108a, 108b, 108c). Extrusion tool (100) according to at least one of the preceding claims 3 to 7, characterized in that the distribution elements (108a, 108b, 108c) or spiral distributors (108a, 108b, 108c) are spaced apart from one another essentially in the axial direction, in particular the direction of extrusion and/ or are arranged one behind the other and/or are pushed into one another and/or that the at least one secondary channel (116a) of the first spiral distributor (108a) and the at least one secondary channel (116b) of the second spiral distributor (108b) essentially in the axial direction, in particular in the direction of extrusion, at a distance from one another and/or arranged one behind the other and/or pushed into one another, and/or that the at least one secondary channel (116b) of the second spiral distributor (108b) and the at least one secondary channel ( 116c) of the third spiral distributor (108c) are spaced apart from one another and/or arranged one behind the other and/or pushed into one another essentially in the axial direction, in particular the extrusion direction. Extrusion tool (100) according to at least one of the preceding claims 3 to 8, characterized in that the distribution elements (108a, 108b, 108c) or spiral distributors (108a, 108b, 108c) are spaced apart from one another essentially in the radial direction and/or arranged one behind the other and/or are pushed into one another and/or that the at least one secondary channel (116a) of the first spiral distributor (108a) and the at least one secondary channel (116b) of the second spiral distributor (108b) are essentially spaced apart from one another in the radial direction and/or arranged one behind the other and/ or pushed into one another, and/or that the at least one secondary channel (116b) of the second spiral distributor (108b) and the at least one secondary channel (116c) of the third spiral distributor (108c) are essentially spaced apart from one another in the radial direction and/or are arranged one behind the other and/or are pushed into each other. Extrusion tool (100) according to at least one of the preceding claims 3 to 9, characterized in that the distribution elements (108a, 108b, 108c) or spiral distributors (108a, 108b, 108c), in particular in the axial direction, such as the direction of extrusion, are essentially concentric or are arranged eccentrically, in particular with respect to the extrusion axis. Extrusion tool (100) according to at least one of the preceding claims 2 to 10, characterized in that the second melt channel (104b) and the third melt channel (104c) in the direction of the melt outlet (106) into a common annular melt channel (118), such as annular gap melt channel ( 118), pass over, the first being Melt channel (104a) and the annular melt channel (118) are thermally separated from one another at least in sections. Extrusion tool (100) according to claim 11, characterized in that the annular melt channel (118) is formed and/or delimited at least in sections by the connecting piece (110) and a housing section (120) of the extrusion tool (100). Extrusion tool (100) according to Claim 11 or 12, characterized in that the first melt channel (104a) opens further downstream in the axial direction, such as the direction of extrusion, into the annular melt channel (118). Extrusion tool (100) according to at least one of the preceding claims, characterized in that a plurality of melt channels (104a, 104b, 104c) and/or a plurality of distribution elements (108a, 108b, 108c) are provided, the plurality of melt channels (104a, 104b, 104c) are thermally separated from one another at least in sections and/or the plurality of distribution elements (108a, 108b, 108c) are thermally separated from one another at least in sections. Extrusion tool (100) according to at least one of the preceding claims, characterized in that the thermal separation is formed by a gap (124) and/or a cavity (128) and/or by an insulating element (126, 130, 132). Extrusion tool (100) according to Claim 15, characterized in that the insulating element (126, 130, 132) is designed as an insulating sleeve (130) or insulating bushing (132) and/or that the insulating element (126, 130, 132) is made of plastic, insulating material , in particular wool, such as mineral wool, and/or metal, such as steel, in particular made of a steel with a low coefficient of thermal conductivity, such as stainless steel, or has at least one of them. Extrusion tool (100) according to Claim 15 or 16, characterized in that the insulation element (126) as an intermediate piece (126) and/or connecting piece (126) for at least one distribution element (108a, 108b, 108c), in particular for the first distribution element (108a ), is trained. Extrusion tool (100) according to Claim 15 or 16, characterized in that the insulating element (126, 130, 132) or the insulating sleeve (130) or insulating bushing (132) around at least a section of a melt channel (104a, 104b, 104c), in particular is arranged around at least a section of the first melt channel (104a) and/or has at least one heating and/or cooling element. Extrusion tool (100) according to at least one of the preceding claims 15 to 18, characterized in that the gap (124) and/or cavity (128) is filled with a temperature control medium, such as a heating medium or coolant, in particular with a gas such as air, and/or is and/or can be filled with a fluid such as water and/or oil and/or that a vacuum is essentially provided and/or generated in the gap (124) and/or cavity (128). Extrusion tool (100) according to at least one of the preceding claims, characterized in that the thermal separation and/or the insulation element (126, 130, 132) is designed as a coating, in particular an insulation coating. Extrusion tool (100) according to at least one of the preceding claims, characterized in that at least one section of a melt channel (104a, 104b, 104c), in particular at least one section of the first melt channel (104a), is essentially floating. Extrusion system comprising at least one extruder; and an extrusion tool (100) according to at least one of the preceding claims. Extrusion system according to Claim 22, characterized in that an extruder is provided for each melt inlet (102a, 102b, 102c) of the extrusion die (100). Extrusion system according to Claim 22 or 23, characterized in that one, in particular common, extruder is provided for at least two melt inlets (102a, 102b, 102c) of the extrusion die (100).